Nuclear propulsion will open vast horizons to the future of mankind. I think the best option will be fusion-powered plasma turbines. http://youtu.be/ro5-QYqqxzM
I was going to say it looks like a Bussard IEC (Inertial Electrostatic Containment) with a VASIMR (Variable Specific Impulse Magnetoplasma Rocket) tacked on the back, but there's a dozen things about the IEC that they're talking that seem different, and they spent little enough time detailing the thruster that comparisons v.s. VASIMR are a little tricky.
There are a lot of key differences. Bussard IEC can be characterized by recirculation of electrons, virtual cathode, "wiffleball" magnetic compression. VASIMR can be characterized by helicon antenna, single phase instead of multiphase.
Lol, wikipedia: http://en.wikipedia.org/wiki/Polywell http://en.wikipedia.org/wiki/VASIMR